José Manuel Colom Maciej Koutny Application and Theory of Petri Nets 2001, 22nd International Conference, ICATPN 2001, Newcastle upon Tyne, UK, June 25-29, 2001, Proceedings ICATPN Lecture Notes in Computer Science 2075 Springer 2001 3-540-42252-8 db/conf/apn/icatpn2001.html